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Twilio Client: A New Way to Phone

Twilio Client extends the power of Twilio beyond the traditional telephone
network. In the past, the only way to transport audio into and out of Twilio was
via PSTN
using telephones. With Twilio Client you are no longer restricted to building
Twilio applications that rely on interacting with traditional telephones. And
best of all, your existing applications will already work with Twilio Client.

You setup your device and establish a connection to Twilio. Audio from your
device's microphone is sent to Twilio, and Twilio plays audio through your
device's speakers, like on a normal phone call. But with Twilio Client, your
device need not be a phone.

When you initiate a connection using Twilio Client, you're not connecting to
another phone directly. Rather, you're connecting to Twilio and instructing
Twilio to fetch TwiML from your server to handle the connection. This is
analogous to the way Twilio handles incoming calls from a real phone. All the
same TwiML verbs and nouns that are available for handling Twilio Voice calls
are also available for handling Twilio Client connections.
We've also added a new <Client> noun for dialing to a Client.

Because Twilio Client connections aren't made to a specific phone number,
Twilio relies on a Twilio Application within your account
to determine how to interact with your server. A Twilio Application is just a
convenient way to store a set of URLs, like the VoiceUrl and SmsUrl on
a phone number, but without locking them to a specific phone number. This makes
Twilio Applications perfect for handling connections from Twilio Client
(which is actually why we created them in the first place).

So when your device initiates a Twilio Client connection to Twilio, a request
is made to the VoiceUrl property of an Application within your account.
You specify the Application you're connecting to with a
Capability Token. Twilio uses the TwiML response from its
request to that Application's VoiceUrl to direct what happens with the
Client connection.